<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>gezi</title>
    <style> 
        .a{
            width: 200px;
            height: 200px;
            border: 1px solid  black;
        }
        .b{ 
            width: 8px;
            height: 8px;
            border: 1px black solid;
        }
        .c{
            background-color: yellow;
        } 
        .g{
            background-color:blue;
        }
    </style>
</head>
<body>
    <div class="a" id="a"> </div>
</body>
<script>    
var inti = function(){
    var a = document.getElementById("a");
    for(var i=1,i<=400,i++ ){
         var div = document.createlement("div");
         div.className="b c";
         big.appendChild(div);var b = document.createElement("div");

    }
}
inti();
</script>
</html>